432 
200' 
MEIS-II data. The data were contrast stretched by 
using a linear or log transform and displayed on the 
colour video monitor. The same analysis procedure as 
that used for the MEIS-II data was then followed 
(Table 3). 
RESULTS AND DISCUSSION 
Approximately 50% of the study area was sketch mapped 
to show four levels of infestation. The sketch maps 
were then used as ground data during the detailed 
photointerpretation of the infrared aerial photo 
graphs. A 1:25,000 scale map was then produced. 
Four levels of infestation: light (0-25%), moderate 
(26-50%), heavy (51-75%) and severe (76-100%) were 
detected and mapped using the aerial photographs. 
This map acted as ground data for analysis of the 
MEIS-II and TM data. 
MEIS-II data 
A number of contrast-stretched band combinations were 
displayed to determine which gave the best indication 
and separation of spruce budworm infestation, healthy 
spruce, and other vegetation types at 5.5 m spatial 
resolution. Band 2 (red), band 4 (green), and band 5 
(blue) gave a natural colour image with the budworm 
infested areas appearing reddish-brown. Some confu 
sion occurred however with treed bogs, mixed white 
spruce and black spruce, and some healthy white 
spruce (Figure 2). The greatest confusion was 
between budworm infested spruce and the vegetated 
wetland areas which occupied a substantial part of 
the study area. Other band combinations which gave 
good visual separation were: 1) band 5 (red), band 4 
(green), band 2 (blue); 2) band 4 (red), band 7 
(green), and band 8 (blue); 3) band 8 (red), band 6 
(green) and band 2 (blue). The analysis of various 
band combinations and comparison to the aerial photo 
graphy was done on a visual basis only. In drier 
parts of the study area, separation of budworm infes 
tation from other vegetation types was much easier. 
At the visual analysis level it was only possible to 
detect the severe level of infestation, although 
there was some indication of the moderate level of 
infestation. Areas of light infestation had a 
reflectance signature similar to healthy spruce. 
Separation between healthy and budworm infested 
white sprue was dependent on the bands used and 
training areas chosen. If great care was taken to 
obtain only the purest possible reflectance values 
for budworm infestation and healthy spruce, then the 
overlap was minimized (Figure 2). Bands 7 and 5 gave 
the least overlap (Figure 3). 
When the 5.5 m resolution MEIS-II data was 
resampled to 10 m, reflectance signatures for healthy 
spruce overlapped part of the budworm infestation 
signature (Figures 4 and 5). Again, separation was 
dependent on the bands chosen and the purity of the 
training areas. The lower spatial resolution also 
seemed to have an effect since radiance values are 
now averaged. Visual separation of the healthy and 
budworm infested spruce was only possible at the 
severe level. There seemed to be greater confusion 
between budworm infestation, the wetland areas and 
black spruce than in the original 5.5 m resolution 
data. Bands 8 and 5 and bands 7 and 5 gave the best 
separation (Figures 4 and 5). 
The results of principal component enhancement did 
not improve upon contrast stretching. Good separa 
tion was obtained by using healthy spruce and budworm 
infested areas as training areas. The Martin Taylor 
enhancement gave good separation in some areas but 
did not improve on the contrast stretched raw data. 
Biomass indices were obtained for several bands. 
The best separation of white spruce from other vege 
tation types was obtained by displaying the biomass 
index of bands 8 and 6, bands 3 and 5, and bands 7 
and 2. The infested white spruce appeared as a light 
Figure 2. Scattergram outlines of MEIS-II bands 2 and 8 
for four classes at 5.5 m resolution. 
Healthy 
white 
spruce 
Budworm infested white spruce 
0' 
.66 - .69 micrometer intensity 
Figure 3. Scattergran outlines of MEIS-II bands 5 and 7 
for five classes at 5.5 m resolution. 
Black/ 
spruceV, 
J Aspen 
\Budworm infested white spruce 
]Healthy white spruce 
Q Water 
o 50 100 150 200 250 
.66 - .69 micrometer intensity 
Figure 4. Scattergram outlines of MEIS-II bands 5 and 8 
for five classes at 10 m resolution. 
green colour while healthy white spruce and black 
spruce were darker. Separation between healthy and 
infested white spruce was therefore dependent on 
being able to distinguish between shades of green. 
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